The invention relates to a circuit arrangement for feeding electrical users from a remote feed apparatus by means of a DC series feed from at least one current source. At least one user is connectable to the remote feed circuit via a DC-DC converter at various locations of the remote feed circuit. The DC-DC converter contains a switch controller for generating a DC voltage from constant current. A switch element is positioned parallel to an input of the first switch controller. A control circuit controls the DC-DC converter dependent on a DC voltage to be held at least approximately constant. A diode is provided between the switch element and a capacitor connected parallel to an output of the switch controller. The diode is poled such that the diode is inhibited given a conductive switch element.
Such a circuit arrangement is already disclosed by German OS No. 32 42 023 or by German No. OS 32 21 404, both incorporated herein by reference.
The circuit arrangement of German No. OS 32 42 023 discloses a constant-current-fed converter which generates a constant, potential-separated voltage for a variable load in such fashion that a correspondingly controlled inductor converter converts a variably accepted voltage into a stabilized voltage. The stabilized voltage is somewhat higher than the input voltage allocated to the maximum power. The output voltage is generated in potential-separated manner from the stabilized voltage by an uncontrolled flow converter.
When a plurality of such circuit arrangements have their inputs at a common feed circuit, and when the constant current source feeding the feed circuit is switched on, then the voltage to be exerted by the constant current source must be significantly higher under certain conditions than the maximum voltage which must be made available for the intended operating modes.
Furthermore, a protection against influencing currents is not possible without further work for such devices since they reduce their input voltage with increasing input current. Also, overvoltage arresters usual for ohmic load users, for example, do not respond. The high currents which then flow can, however, destroy the device.